Factor 1 Plus Mens Long Sleeve Zip Neck Base Layer Tops offer greater neck protection than standard round neck versions, as well as allowing greater aeration should you start to overheat during exercise. 

Manufactured from super soft 100% polyamide fabric, these base layer tops utilise body mapping technology to construct innovative seamless body forms, enabling features such as stretch rib zones for support and waffle zones for enhanced heat retention and greater perspiration control. 

 The set-in sleeves provide a much more tailored fit in the armpits, maximising insulation and moisture transportation (wicking), whilst the seam on the sleeve length allows the addition of a thumb hole near to the cuff. This allows the wearer to place further layers on top of the base layer without the sleeves riding up, and can also protect the palm of the hand from cold weather. The stand-up double thickness turtle neck features a 18cm / 7inch low profile lightweight zip with a double fabric chin guard. Body lengths in all our base layer and mid layer designs are long,  giving the wearer a decent amount of fabric to tuck in to their trousers. This helps to avoid lower back exposure during activities and when sitting down.

These Sub Zero zip tops are one of the best lightweight thermal underwear ranges for general outdoor use. The multi-functional design makes them compatible with most sports where you need to keep warm and dry but also provide extra neck protection. They cross over in to anything from skiing through to hiking and camping, and can be used in combination with the Sub Zero Factor 2 thermal mid layer range for extra warmth in extreme conditions.